:root{
    --theme_color:black;
    --theme_vary_color:white;
    --theme_text_color:white;
    --usual_text_size:16px;
    --usual_title_size:20px;
    --usual_linear_color:#888;
    --usual_description_color:#444;
    --usual_description_size:14px;
}
*{
    padding: 0px;
    margin: 0px;
    box-sizing: border-box;
}
*::selection{
    background-color: var(--theme_color);
    color: var(--theme_vary_color);
}
p{
    margin: 20px auto;

}
a,a:hover{
    text-decoration: none;
}
ul{
    list-style: none;
}
.limited_text{
    display: -webkit-box;
    -webkit-box-orient: vertical;
    text-overflow: ellipsis;
    overflow: hidden;
}
.limited_single{
    white-space: nowrap;
    text-overflow: ellipsis;
    overflow: hidden;
}
.com_width{
    width: 1500px;
    margin: auto;
}
.paragraph_img{
    width: 70%;
    margin: auto;
}
.paragraph_title{
    font-weight: bold;
    font-size: 16px;
}
@media (max-width:1500px) {
    .com_width{
        width: 100%;
        padding: 0 20px;
        box-sizing: border-box;
    }
}